Googles (sic) left bias has created a politically correct monoculture, the engineer wrote.

Distribution of preferences and abilities of men and women differ in part due to biological causes and that these differences may explain why we dont (sic) see equal representation of women in tech and leadership, the engineer added.

Google said it would not publicly comment on individual employee cases, however chief executive Sundar Pichai told employees that portions of the memo violate our code of conduct and cross the line by advancing harmful gender stereotypes in our workplace.

The search giant’s vice president of diversity, Danielle Brown, sent a memo in response, arguing that the engineer’s email essay advanced incorrect assumptions about gender.

Mr Damore informed Reuters that he was now exploring all possible legal remedies.

He said that before his dismissal he had submitted a charge to the US National Labor Relations Board (NLRB) accusing Google’s senior management of attempting to shame him into silence.

It’s illegal to retaliate against an NLRB charge, he said.

The US National Labor Relations Act guarantees workers the right to engage in concerted activities for their mutual aid or protection.

Alison Morantz, a Stanford University law professor with expertise in labour law, said it was unclear how that was applicable to his dismissal.

It’s going to be a hard sell that this activity was either concerted or for mutual aid or protection, rather than simply venting or pitting one group of workers against the others, which does not sound very mutual, Ms Morantz said.